Internal-combustion percussive engine.



L. L. SCOTT. INTERNAL COMBUSTION PERGUSSIVE ENGINE. APPLIUATION FILED111111.11, 1912.

1,058,268., Patented Apr. 8, 1913.

ATTORNEY thereof;

i .UNITED sTATEs PATENT ormoni .4 I LEWIS L. SCOTT, 0F ST. LOUIS,MISSOURI, ASSIGNOR TO SCOTT LOUIS, MISSOURI, A CORPORATIONOF MISSOURI.

DRILL COMPANY, OF ST.

INTLRruir.-colvmusrronA PERcUssIvE ENGINE."

Patented Apri s, 1913.

Application led March 1i, 1912. Serial No. 6&3,015..

To all whom t may concern.'

Be it known that I, LEWIS L. SCOTT, a citizen of the United States,residing at St. Louis, Missouri, have'invented a certain new and usefulImprovement in Internal-Combustion Percussive Engines, of which thefollowing is a full, clear, and exact description, such as will enableothers skilled in the art to which it appertains to make and use thesame, referencebeing had to the accompanying drawings, forming part ofthis specification, in' which- Figure 1 is' a vert-ical longitudinalsection of an engine constructed in accordance with my invention. Fig. 2is a sectional view on line A-A of Fig. 1. Fig. 3 is a top plan Viewpartly in horizontal section. Fig. 4 is a sectional view on line B-#B ofFig. 2.

This invention relates to improvements in internal combustion percussiveengines intended to be used particularly in connection with rock drillsand the like.

The object of my present invention is to provide means for lholding theexplosive pressure within the firing chamber until the piston strikesthe end of the block or drill so as to obtain the driving blow on theend of the saine.

Another object is to provide improved means for cushioning theconnect-ion between the piston and crank-shaft, the hammer piston beingfree from the crank shaft when the blow is struck.

In the drawings, l indicates the cylinder and 2 the explosion chamber atthe rear end 3 is the compression chamber which receives the charge of,mixed air and gas through port 4 and channel 44.

5 is t-he head which closes the front end of the chamber in cylinder 1and 47 is the head which closesthe rear end of said cylinder,

. the latter head being ported and providing a mount for check valve 37held to its Seatby a spring 38 whereby the compressed charge of air andgas is admitted to the chamber 2. Head 5 affords .a mount for means forr0- tating chuck 6. Y l

7 indicates a piston adapted to reciprocate in cylinder 1,said pistonhaving a hammer head S designed to strike a block 9 mounted in head 5through which the blow is transmitted to the drill 10.

Where it is desired to rotate the drill lugs i 11 are provided on drill10, lwhich lugs t in slotsl in the chuck 6 s0 that if the chuck isrotated the drill is rotated in unison therewith. Chuck 6 is providedwith Worm te'eth 12, preferably at its inner end, .and which operate inan internal for circumferential groove in the head 5 which Worm teeth-mesh with a worm 13 mount/eden a shaft- 14.4

Shaft 14 is intermittently rotated by means of an eccentric 15 'carriedby the main shaft 16 so as to oscillate the yoke or rock arm 17 (mountedon the end of shaft 14) by means of the connect-ing pitman rod 18. Theoscillation of arm 17 intermittent-ly rotates4 i shaft 14 by means of aratchet' and pawl mechanism or by means of collar 19 mounted on theshaft 14 and held in frictional engagement with said shaft by a spring20 bearing therebetween and a collar 21 threaded on the shaft. Thiscollar 19 has a clutch face engaging a clutch member 19a on shaft 14, asshown in Fig. 2. A roller 22 is mounted in the inclined slot 23in thearm 17, as shown in Fig. 4, so that when the arm 17A is rocked in onedirect-ion, shaft 14 will be rotated, while the movement of the arm inthe opposite "direction permits' the shaft to remain stationary, thisrecovering of arm 17 causing the roller to be moved against a shoulder24 in the arm 17. The object of thus providing a friction drive` for thedrill is to prevent the breakage of parts in the. event that the drillbecomes wedged in the drill hole. l n

Piston 7, before referred to, is bored to receive 'a piston25,`preferably introduced through the open end of the bore, which rearend is {closed by a removable head 26. A cross pin 27 is carried bypiston 25,'the ends of said pin extending through slots 33 in the walls,ofl the piston 7 and slots 34 in the/walls of cylinder 1 and areconnected to pitman rods 28 and29. Rod'28 is connectyed tocrank pin 30carried by main shaft 16,

while the rod 29 is connected to an eccentric 3l whose throw is equal tothat of the crank pin 30. A fly Wheel 32 is mounted upon one end ofshaft 1'6.

35 and 36 are ports cut in the side of piston 7 to permit air atatiriospheric pressure to enter the spaces 45 and 48 between the ends ofpistons 7 and 25. These ports are located a little distance from the endof the chamber in the piston 7 se as to provide a vio euehien betweenare pistone fr ena' 25, ee Win be explained later, although 1n practiceit is not absolutely necessary to .use the cushion chamber 48.

5 The charge of mixed air and. gas enters chamber 2 of cylinder 1through valve 37 which valve is normally held closed by spring 38,before referredto.

39 indicates an exhaust valve for the spent gases, said valve beingnormally held closed by means of a spring' 40. This valve 39 may bedispensed with if desired.

41 indicates a cam secured to shaft 16 and which coperates with theroller 42 on the 1.5 end of the valve rod 43'which carries the valve 39.Any form of mixing valve may be attached to port 4.

The operation is as follows: The mixed air and gas is drawn into chamber3 through 20 port 4 and 'channel 44 on the retracting by means of aspark arrangement commonly used in gasolene engines. Piston 7 will nowbe driven outward under the pressure of the explosion and' will, throughthe hammer head 8, strike the block- 9, theblow being transmitted to theydrill 10. Hammer 8 strikes block 9 before crank 16 reaches its deadcenter and also before the pressure isrelieved in chamber 2 by valve'39.The momentum of the fly wheel causes the crank to continue its movementso that piston 25 will move outward independently .of the piston 7 andallow thecrank shaft to pass its dead center without the end of piston25 contacting with piston 7 and therefore without shock to its bearingsas the'air between the end -of piston 25 and piston 27 forms av cushion.As the piston 25 moves outwardly it uncovers port 36 and lets air atatmospheric pressure enter space 45 between the two pistons, and thus aneffective cushion between the pistons on the return stroke is providedwhich cushions the piston 25 against the shock of the explosion behindpiston 7. The exhaust valve is opened and closed during the outwardindependent movement of piston 25, and as the crank passes its deadcenter and starts on the back stroke, piston 25 will compress the air inchamber 45 until the piston 7 is caused to move-therewith. Port 435 isuncovered on the back stroke and air at atmospheric pressure will enterthe chamber 48 so as to provide a cushion between the outer ends vof thetwo 65 pistons to absorb any shock due to a reigo'aaeea' bound of piston7 in striking ,its blow. As these operations continue, it will beapparent that explosions occur in chamber 2 on every out stroke and whenpiston 7 approaches the end of its out stroke it will, through itsenergy, strike the block 9 and at the time of delivering such a blow beabsolutely free from the crank shaft. At the time of striking its blowthe explosive pressure is behind the pist-on 7, thereby making the blowvery effective. rllherotation of the drilling tool .will occur, asbefore described and water or air may be run through the steel drillforv the purpose of removing 'cuttings from the drill hole, connectionsfor same being made 30 lat 46 (Fig. l). In operation piston 7practically becomes a floating piston entirely in-` dependent from thecrank shaft and its bearings and has a dilferential stroke withrespectto the internal piston 25. rIhe stroke of piston 25 is determined by itsconnections to shaft 1G rand may be said to be fixed.

For purposes distinguished in the following claims I shall designatepiston 25 as aninternal piston and floating piston 7 as an externalpiston.'

What I claim is:

1. In an internal combustionl percussive engine, the combination of acylinder having valved ports for t-he admission of air and gas and theexhaustion of the spent gases, a floating piston operating in .saidcylinder and an internal fixed-stroke piston operating within thefloating piston, said pistons being moved in a forward direction by theexpansion of exploded gas within the cylinder, and a crank shaftconnected with the fixed stroke piston and operable to move the pistonson the rearward stroke.

2. In an explosive engine of the character described, the combination ofa' cylinder, a floating piston therein, an internal fixed stroke piston,.said pistons having differen tial movement, lsaid cylinderbeing adaptedfor the explosion of gas therein to move said pistons, means forproviding cushions between the .ends of said pistons, a shaft rotated bythe lixed stroke piston on the forward movement of the pistons andoperating to return the pistons on the rearward stroke, and means forcontrolling the admission and exhaust of gas to and from the cylinder.

3. In an explosive engine of the character described, the combination ofa cylinder, a floating piston therein adapted to cooperate with adrilling device, an internal piston, a drilling device for receiving ablow from the external piston, a shaft rotated by the internal piston,an exhaust valve, and means operable by said shaft for opening theexhaust valve after the external iston has delivered its blow upon thedrilllng device. e'

4..In anexplosive enginexof the character. described, the combinationvof a cylinder,

an external lioating piston'a'ndl anlnternal. 13

fixed-stroke piston, a drilling device with.

. which the loatlng piston coperates, a shaft connected to the internalpiston, and means l operated by said" drilling device.

5. In an explosive engine of the character described, the combination ofa cylinder, an external Heating piston and an lnternal fixed-strokepiston, a hammer blockwith which the floating piston coperates, a'shaftshaft for rotating said connected to the internal piston, a drill rangedwithin the floating piston, 'a pin carrie by said internal piston, andhaving an end projecting through said alined slots, a shaft, andconnections between said pin andl shaft for driving the latter.

In an explosive engine of the character described, the combination of acylinder, a drilling device mounted p cylinder, two istons mounted.within the cylinder, one o said pistons being arran ed within the other,one of said pistons belng in the nature of a fioatin signed to operatethe dri ing device, the oter of said pistons having a fixed stroke, acrank shaft piston and adapted to move said pistons away from thedrilling device, and means for providing al cushion between said pls--tons.

8. In an explosive engine of the character described, the combnatlon ofa slotted cylinder, a. drilling device mounted in one end ofsaidcylinder, two pistons arranged withoneof said istons being containedby the other, one o said pistonsbeing in the nature of a fioating pistonadapted to strike the drilling device, and the other of said pistonshaving a fixed stroke, a crank shaft adapted to receive energy from saidpistons on their forward stroke for the purpose of moving them on theirrearward stroke, and a pin carried by said fixed stroke piston todeliver impactupon at one end of thev piston and deoperated by the lastmentionedl e ing piston. coperates andl projecting through the Vslottedcylinder, and connected to said shaft to dperate the same. A

`9. In a device of the class described, the combination, of a cylinderprovided with an ex losion chamber, a oating piston in said cy 'nder inoperative relation to said explos1on chamber, an anvil with which saidfloating piston coperates, an inner piston slidingly mounted in saidfloating piston, a crank the explosion chamber, and means for operatingsaid shaft from said inner piston.

shaft for moving said pistons toward 10. In a Vpercussive engine of thecharacy ter described, the combination of a cylinder having-anvexplosion chamber and a charge receiving chamberzo means for introducingan explosive duid `1nto the charge-receiving chamber and transmittingsaid fluid to said explosion chamber, means for exploding the fluid inthe explosion chamber,two pistons arranged withln the cylinder, one ofsaid pistons being mounted within the other, said diEerentialmoveplstons having relatively istons bein ment, one of said liverimpact, and the other having a fixed stroke, a drilling device forreceiving a blow from the fioatin piston, and a crank shaft operated bythe ing the pistons on the rearward stroke. Y

11. In a ter described, .in combination, a cylinder providedwith anexplosion chamber and a charge receiving chamber, said chambers betionwhereby a charge may be conveyed from the latter to the former, aHeating piston operating within said cylinder and ada ted to deliverblows under the inuence of charges exploded inthe explosion chamber, adrilling device with which said ioata fixed stroke piston adapted tomove with said Boating piston, and a crank shaft operatively connectedwith said xed stroke piston whereby said pistons are retracted on theirrearward stroke. g

In testimon whereof I hereunto ax my si ature in e presence of twowitnesses,

, this 7th day of March, 1912.

, LEWIS vL. scorn` Witnesses:

M. P. Smm, C. S. Bum

percussive engine of the characing provided with a means of communicainthe na` I Vture of'a oating piston and a' apted to dexed stroke pistonfor movv

